Refrigerating method and apparatus



July 23, 1946. N E, MacLEAN 2,404,511 I REFRIGERATING METHOD AND APPARATUS Filed Jan. 18, 1944 2 Sheets-Sheet 1 THE RMOS TAT v INVENTOR. NORMA/V E. .MACLEAN A 770F415 rs i a l z I);

July 23 1946. MacLEAN 2,404,511 I REFRIGERATING METHOD AND APPARATUS Filed Jan. 18', 1944 2 Shets-Sfieet 2 INVENTOR. NORMAN E. MACtEA/V ATTORNEYS Patented July 23, 1946 REFRIGERATINGMETHOD ANDAPPARATUS Norman E. MacLean, San Francisco, Calif.

Application January 18, 1944, SerialNo. 518,769

" This invention relates to refrigeration, and particularly to a method and apparatu for producing low temperatures in large and small spaces at very low cost. The inventionutilizes carbon dioxide as a refrigerant and is therefore particularly adaptable to use Where a supply of carbon dioxide is available. extract carbon dioxide from stack gase'sso the invention is ideal for-use" on ships where carbon dioxide i commonly usedand can be easily produced from stack gases for fire extinguishing and fumigation at extremely low cost. g Y

' Generally speaking, refrigeration of large spaces is-accomplished in two phases'jnamely, primary refrigeration in which heat is absorbed direct by ther re frigerant"itself and secondary refrigeration in'which heat istransferred from the air of space to be refrigerated to a cooled brine! This invention iutilizes carbondioxide in tW'odifferent' forms, both as-a primaryand-secondary-refr'igerant. v

It is'the object of the invention to provide a method and apparatusfor refrigeration inwnichcarbon'dioxide is utilized with a high degree of efiiciency, both as primary and secondary refrigerant. A further object of the invention is to provide refrigeration by means of a the-nnosiphonic flowi of liquid carbon dioxide as a brine in a closed circuit whichis. maintainedat a low temperature by theme of solidcarbon dioxide or CO2 snow. d a

A further object of the invention is to provide refrigeration utilizing carbon ."dioxide' as. a' brine and as a coolant forthe brine; with carbonidiox idefor both purposes originating from the same source andbeing largely recoverable to prevent waste. d d I Further objectsand advantages aremade apparent in the following specification'wherein ref.-

erence is-made to the accompanying drawings. illustrating a particular form of the invention.

In the drawings:

Fig. 1 is a vertical sectional view taken'throu gh" a refrigerating apparatus embodying the present invention; and l 1 Fig. 2 is a horizontal sectional view of the same apparatus showing a diagrammatic circuit" for condensing and storing recovered gases.-

. The drawings show an insulated chamberv with an access door II. A closed circuit liquid circulating system' is disposed. partially Withinand partially without the chamber Hi. :This sys tem includes a heat exchange unit consisting of, a plurality of pipes I2 betweenmanifold l3 andv l4 withinthe chamber and asimilanunit consist It is current practice to 11 Claims. (Cl. 62-915) 2 ing of pipes l5 and manifolds l6 and I1 just outside theunit. The pipes l2 and I5 in the two heat exchange units may be provided with conventional fins spines or any other suitable device for enlarging their surfaceafor the purpose of increasing their capacity forgtransmittingheat. A liquid, in this case carbon dioxide in liquid form, enters the system through a pipe l8 and valve l9 and passes through a'surge chamberZO and then through a pipe 2 I communicating with the heat exchanger 12 where it is cooled by the presence of CO2 snowin the chamber H1. The

liquid thus cooled passes through a pipe 22 and valve 23 to the heat exchanger- I5 and then through apipe24 back to the surge chamber 20.

A duct 25 encloses the heat exchange unit l5 and a blowerjzfi driven by a motor 2'! draws air from the areato be cooled through the'duct and over theheat exchanger. The rear end of the duct 25'is spaced from the chamber it and supportedby straps 28 toadmit the air to be cooled. The air, after being so cooled, is ejected from the exhaustend of the blower 26, as indicatedby arrowsin Fig.2. The exhaust of the blower may. of course be directed with suitable conductance to direct-this air to any desired point. I When the liquid circulating system which in cludes the two heat exchangers l2 andlfi has been filled through the pipe l8, the'valve I9 is closed and the liquid circulates continuously in the closed circuit by thermo-siphonic action.

Thi action is maintained by a-quantity of CO2.

snow 'Within the chamber which is indicated at 29 in Fig. l'as completely covering the heat exchanger 12. As the liquid in the'heat exchanger I5 absorbs heat from the flow of air over thi exchanger, it is brought tov a temperature higher than its boiling point which in the case of carbon dioxide is l09,3 F. This causes the liquid to rise and set up the thermo siphonic flow desired.

Whatever vapor is created is,of course, condensed and cooled as it enters the refrigerating chamber l0 and is brought to a very low temperature as it again flows through the'heat exchanger 12 therein.

The surge chamber-2'0 which is included in the circulating system is o l partially filled with liquid and allows-space for the ebullient action resulting from the increasedtemperature of'the liquid in the heat exchanger I5. A gas expan; sion drum communicates with the surge'chamher through a pipe 3| and permits expansion in the system in the event that the supply '0f ;CO.i

snow is depleted during the operation,'or while the-system is notoperating .Asafety valve 3'2 with the system to accommodate expansion of the carbon dioxide due to increase in temperature when the supply of snow in the refrigerating chamber is depleted.

5. Refrigerating apparatus comprising a chamher, a circulating system disposed partially inside and partially outside of said chamber, a single source of carbon dioxide underpressure to supply liquid carbon dioxide to said system, and means arranged to cooperate with said source and with said system to deposit carbon dioxide snow within the chamber.

6. Refrigerating apparatus comprising a chamher, a circulating system disposed partially inside and partially outside of said chamber, a single source of carbon dioxide under pressure to supply liquid carbon dioxide to said system, means arranged to cooperate with said source and withv said system to deposit carbon dioxide snow within the chamber, and means to vent the flash gas and product of sublimation from the snow within the chamber.

'7. Refrigertaing apparatus comprising a chamber, a circulating system disposed partially inside and partially outside of said chamber, a single source of carbon dioxide under pressure to supply liquid carbon dioxide to said system, means arranged to cooperate with said source and with said system to deposit carbon dioxidesnow within the chamber, and means to vent and posed heat exchanger outside the chamber, means to supply liquid carbon dioxide to the system, an expansion nozzle within the chamber, and valve controlled by-pass means to admit a quantity of carbon dioxide to said nozzle to produce a covering of carbon dioxide snow on the heat exchanger within the chamber.

10. Refrigerating apparatus comprising a refrigerating chamber, a fluid circulating system including a heat exchanger disposed inside the refrigerating-chamber and a heat exchanger disposed outside the refrigerating chamber, means to supply liquid carbon dioxide to said system,

means controllable to release a quantity of said carbon dioxide to deposit snow on the heat exchanger inside the refrigerating chamber, means to close the system wherebyheat absorbed by the heat exchanger outside the refrigerating chamber will set up a thermo-siphonic flow of liquid carbon dioxide in the circulating system, an expansion chamber in communication with the system to accommodate expansion of the 7 carbon dioxide due to increase in temperature recover the flash gas and product of sublimation I from the snow within the chamber.

8. A refrigerating apparatus comprising anormally closed system for the circulation of liquid carbon dioxide, means to form carbon dioxide snow and deposit a quantity of the same on a portion of said system, a single source of supply of carbon dioxide under pressure, means for directing carbon dioxide from said source to said system, and means for directing carbon dioxide from said source to said snow forming means.

9. A refrigerating apparatus comprising a chamber, a liquid circulating system including a horizontally disposed heat exchanger within the chamber adjacent its bottom and a vertically diswhen the supply of snow in the refrigerating chamber is depleted and a precooler expansion drum in communication with the system inside therefrigerating chamberto increase the; yield of expanded carbon dioxide snow.

11. A refrigerating apparatus comprising a closed chamber, a liquidgcirculation system in-' cluding a horizontally disposed plurality of pipes connected to headers as a heat exchanger within r the chamber adjacent its bottom and a verti- 1 cally disposed heat exchanger outside the chamher, means to supply iquid carbon dioxide under pressure to the system, an expansion nozzle within the chamber, means to admit a quantity of carbon dioxide liquid to said nozzle to produce a covering of carbon dioxide snow on the heat exchanger within the chamber and a thermostatically controlled valve to regulate the thermo-siphonic flow of the liquid carbon dioxide in said system.

i NORMAN E. MACLEAN. 

